Deep fat frying commercial pressure cookers are well known in the art. Prior art workers have also developed numerous types of ventless hoods for such pressure cookers. The most frequently encountered prior art ventless hoods employ a fan to draw the cooking gasses through conventional filter means such as baffle filters, metallic mesh filters and charcoal filters. Prior art workers have also incorporated electrostatic precipitators in such ventless hoods. However, the electrostatic precipitators require constant maintenance.
In addition, prior art workers have incorporated recirculating sheets or sprays of water as filtering means for cooking gasses. It has been determined, however, that ventless hoods using water sheets or sprays are complex in construction. Since the water sheets or sprays work by gravity, they place constraints on the design and size of the ventless hood structure.
The present invention is based upon the discovery that excellent results can be achieved easily and economically through the provision of a water bath into which the cooking gasses are first introduced. A major portion of the vaporized cooking oils and steam are condensed in the water bath. Residual non-condensables, uncondensed steam and cooking oils, and unabsorbed odors are vented directly from the water bath through the inlet side of a hood system which contains baffle filters, a metallic mesh filter and a charcoal filter. Under these circumstances, no electrostatic precipitator is required. An essential feature of the ventless hood assembly of the present invention lies in the use of a radiator (heat exchanger) to cool the water in the water bath so that it will continue to condense the vaporized steam and cooking oils. The radiator is located above the filters in the hood and in advance of a fan which draws the gasses and ambient air through the hood. A pump is provided to pump the water from the water bath through the radiator, the cooled water being returned to the water bath. It has been found essential to cool the water bath, which would otherwise reach the boiling point, resulting in excessive discharge of cooking gasses beneath the hood and through the filters.